Ventilator



. June 19, 1945. H, W5, TR'Osf 2,378,518

VEN TTTTTT R Patented June 19, 1945 f UNITED; STATES PATENT-f oFFl-CE f l vEN'rILnroR.` Henry W. Trost; Rochester,` N. Ye `a's'sgnor yto 'Bausch' 'dtA Lombv Optical Company, Rochester N.r Y., a corporation of New YorkJ 'ApplicationfNoyembr s, 1943; sriaLNq. l509,245 fsolai'ma `(o1. esl-"1213* This. inventio-nfrelatesl .to ventilators. and: more particularly to ventilators vhaving means for permitting. theV passage of air therethrough while preventing the passagerofy light :therethrough Although the :present invention for illustration purposes has been embodied ina projection'apparatus,` itis not to be restrictedto such an ap-v paratus, for/it will beobvious that vit can be used wherever it is desired'to preclude'light-b'ut yet allow `the passage o f air currents.

In prior 'devices of the type hereindescribed, louvers generally arcuately bentand `iormedwith y anti-reflection surfaces have been so closely spaced that light could not pass through the same. l

Many ofgthese prior-devices vprovedv very eli'- cient as light traps butgasV they also restricted thev passage of Vair dcurrents therethrough,` they could not`be-usedwhere-it was necessary for coolingv purposes to passair freely through the The'rv spaced vlouvers they lwere arcuately bent formed zigzagg-ed passages which preclude the passage'of light but which "created eddy currents and restricted the passage of air. yThe angular turns of thepass sages'so'formed oftencaused back pressure to build up within'the'same and, insome devices," it

was extremely` diflicult' toeven forcey air through thesaine; v H

Many devices `heretofore proposed have been a compromise', in that,l the'light preclusion feature ljection apparatus embodying the present inven;

tion. l

Fig. `2"isfa` perspective viewofthe ventilator showing the.method of attaching the louversV to their supporting elements.

Fig. 3 isvan exploded View showing 1an end por'- tion of one of the louversand its supporting member.

In the` preferred embodiment of the invention, the lamp housingA or casing of;the projection apparatus vis lpreferably formed vby four. vertical walls and a bottom wall; I0 indicating one of the side walls; II thefront side wall, I2 the `rear side wall, and I3 the bottom wall. To facilitate the assembly of vthe'projection apparatus, the cas- Y' ing Iis formed with an upper section or container y of these prior devices,A as

has been sacrificed to gain Va morefree-passage for fthe air. f

`T'obviate the difliculties broughtl about bythe zigzagcourse of theA passages formed between ythe louvers, lit has been proposed to' reduce the angularltyof the bends and to improvethe light pre-l clusion, the yedgesV of' the louversl lwere spaced rapart a distance less'than themedial portions of the same. This .formation and positioningofv the louvers restricted'the passages'adjacent the dischargeends thereofmand'produced back pressure particularly acute in forced. air systems.

Itis the; primary object ofthe present invention to 1' provide a ventilator which. will prevent `all light from passing -therethrough but permitthe free flow of air therethrough.

These and other objectsand advantages of the invention residein certain novel features of construction, arrangementiand. combination of parts as will hereinafter be .more fully explained and y pointed out in the appended claims.

Inthedrawingz n Fig.v 1 is a side elevation in section vof a pro- I4 housing the Ventilating means of thepresent invention and a lower section or container I5 in'which are mounted: the conventional optical elementsofk a projection system, the sections being securely joinedfto prevent the escape of light therefrom by the engagement of their respective ii'anges I6 and I'I in anysuitable manner.

The front and rear'side walls II and I2 of the section` I5 have inturned'fianges I8 and I9, respectively, to support the projection apparatus. The'bottom wall I3l of the casing is bent at its edges .to form downwardly extending anges 20 engaging the side walls` of the section I5 and seating upon the flanges 'I8 and I9. The bottom wall has openings 2l serving as entrances for air into the casing and the top of the casing isfopen to permit the heated air to escape from the interior of the casing. Narrow inturn'ed langesZZ of the side walls of the housing'are providedto form stop members forlocating a portion of the ventilating'meansfin the' casing. l

Mounted upon the .bottomwall I3'is a lamp rbase 23` carrying a lamp 24 -and current is sup'n plied to the lamp by a cord, not shown.r 'A reflector 25 is mounted behind the lamp 24 to direct Yrays of light from the' lamp through the alle1 rows, the curved surfaces of the louvers in one row being oppositely disposed relative to the curved surfaces of the louvers,in the other row. Also, each louver in each row is positioned with its curved ends disposed before the medial portion of the preceding louver and in alignment with the medial portion of a louver in the superimposed row. Hence, a chord connecting the ends of a louver will intersect the middle portion of the next adjacent louver.

Referring to Figs. 2 and 3, the louvers are held within the section I4 of the housing by split metal bands 29. These bands have notches 3l formed on their parallel side walls 32 in which are received spaced edge portions 33 of the louvers, the interlocking engagement of these portions of the lil louvers with the bands causing the louversto be v rigidly held within the bands. The metal bands are formed square to engage the inner surfaces of the side walls of the housing and are fastened to the front and rear side walls of the housing by screws 34 passing through openings in these walls and engaging tapped openings in the bands.

It will be apparent that by this arrangement of the louvers, no direct path for the rays of light is had through the louvers.` In order to positively preclude light from escaping from the casing through the louvers, the surfaces of the louvers are coated with an anti-reflection film, which may comprise a matte black lacquer having lightabsorbing properties. Accordingly, rays of light incident upon the louvers will be absorbed and prevented from passing to the outside of the lamp casing.

Furthermore, the formation and positioning of the louvers afford smooth curved passages for the free and unrestricted circulation of air currents therethrough. Thus, when the lamp, which is of the high intensity projection type, is lit, heat is generated and cool outside air is drawn by convection through the openings in the bottom wall of the casing and about the optical elements in the interior of the casing, the heated air passing freely through the passages formed by the louvers to the outside of the casing. As no sharp bends are encountered by the air currents in their passage through the louvers, eddy currents are not created and the free and unrestricted flow of air is insured through the louver passages in such quantity that the air within the housing does not become unduly heated. As a result, the life of the lamp is considerably increased and the expansion of the condensing lens system in its mounting will be minimized, preventing any possibility of the breakage of the same from this source. Also, the casing is not overheated and the operator may safely handle the projection apparatus without danger of burning his hands. Throughout the specification and claims I have used the term louver to designate the lower plates.

From the foregoing, it will be apparent that I am able to attain the objects of my invention and provide a ventilator which will positively preclude light and allow the free and unrestricted passage of air currents therethrough. Various modifications can, of course, be made without departing from the spirit of my invention or the scope of the appended claims.

Iclaim:

1. In a ventilator, in combination, a container having a Ventilating opening therein; and spaced parallel rows of arcuately-shaped louvers mounted positioned with the louvers in endwise relation to each other and to the flow of air through the opening, said louvers having the same radius of curvature and spaced eduidistant from each other in each of said rows, the concave surfaces of the louvers in one row oppositely disposed relative to the concave surfaces of the louvers in the other row to form discontinuous passages for air theren through while preventing the passage of light therethrough.

2. In a ventilator, in combination, a container having a Ventilating opening therein; and spaced parallel rows of arcuately-shaped louvers mounted within said opening, said rows being positioned one above the other and with the louvers of one row in endwise relation to those cf the other row and in endwise relation to the flow of air through the opening, the louvers in each of said rows spaced from each other with the ends of each lou- Ver positioned before `the medial portion of the adjacent louver and with the arcuate surfaces of the louvers in one row positioned opposite to the arcuate surfaces `of the louvers in theV other row to form discontinuous passages for air therethrough while preventing the passage of light therethrough.

3. In a ventilator, in combination, a container having a Ventilating opening therein; spaced paralle1 rows of arcuately-shaped louvers carried within said opening, said rows positioned opposite each other with the louvers of one row in endwise relation to those of another row and the flow of air through the opening", the louvers in each of said rows spaced from each other with the ends oi' each louver disposed before the medial portion of an anterior louver; the ends of each louver in one row being in alignment with the medial portion of a louver in the other of said rows to form passages for air therethrough while preventing the passage of light therethrough; and means engaging the curved Peripheries of said louvers and secured to said container for holding said louvers in said position. A

4. In a ventilator, in combination, a container having a Ventilating opening therein; a plurality of arcuately-shaped louvers having substantially the same radius of curvature and having a notch in each of their curved peripheral edge portions; a plurality of bands having notches engageabie with the spaced edge portions of said louvers for holding said louvers in spaced relation; andv means for mounting said bands in said container with l the louvers disposed in parallel rows within said within said opening, said rows being oppositely Ventilating opening and with the curved surfaces of the louvers in one row oppositely disposed relatiVe to the curved surfaces of the louvers in the other row whereby said louvers form passages for air therethrough while preventing the passage of light therethrough.

5. A ventilator comprising two spaced rows of louvers positioned opposite each other in endwise relation to each other and to the iiow of air, each row comprising a plurality of spaced arcuately curved louvers, the concave surfaces lof all of the louvers in one row facing in the opposite direction from the concave surfaces of all of the louvers in the other row, the louvers being positioned so that the chord connecting the ends of each louver will intersect the medial portion of the next adjacent louver in the row whereby the free passage of air is permitted but the passage of light rays therethrough is prevented.

HENRY w. p TRosT. 

